Percutaneous vertebroplasty is a minimally invasive spinal surgery technique that involves the percutaneous injection of bone cement into the vertebral body through the pedicle or outside the pedicle to increase the strength and stability of the vertebral body, prevent collapse, relieve pain, and even partially restore the height of the vertebral body. Mechanism Introduction 1. Intravertebral injection of self-curing calcium phosphate. Bone cement can significantly restore the mechanical properties of the fractured vertebral body, the degree of recovery is related to the amount of injected bone cement, its strength can reach up to two times the normal case, while the stiffness can exceed the original about 15%; vertebral body fracture after filling the fracture gap and intra-vertebral body space by the arch root CPC can also restore the strength and stiffness of the vertebral body, respectively increased by 16.67% and 11.05%. 2, change the stability of the vertebral body. Calcium phosphate significantly increases the stability of the anterior column and reduces the stresses acting on the pedicle, ultimately leading to enhanced stability after osteoporosis, burst fractures, and internal fixation of the pedicle. Although the results of the studies vary, they all show that vertebroplasty has a significant effect on the stability of the spinal segments in patients with vertebral compression fractures. The increased strength of the vertebral body and the altered rigidity after vertebroplasty may present an additional problem of increased intervertebral disc loading in the upper and lower intervertebral discs, predisposing to disc degeneration or fracture of the adjacent vertebral body. Studies have shown that after the change in vertebral body strength, excessive stiffness can, to a certain extent, cause redistribution of the spinal stress field and displacement field, but there is no significant effect on the stress of adjacent vertebrae after strengthening with CPC vertebrae, and the effect on adjacent discs is also small. 3, relief of spinal pain. In this sense, percutaneous vertebroplasty is a fracture repair technique, not just a simple filling of the vertebral body. Almost all clinical results show pain relief rates of more than 90% in patients with either osteoporotic compression fractures or old thoracolumbar fractures, for reasons for which there is no definite explanation, and which may lie in: (1) microfractures within the vertebral body are stabilized after vertebroplasty; (2) the bone cement takes up a significant portion of the axial stress, thus reducing the micromovement of the fracture line on the nerves within the vertebral body; (3) the vertebral body is stabilized after vertebroplasty (2) the bone cement takes up a significant portion of the axial stress, thus reducing the stimulation of the intravertebral nerves by the micro-motion of the fracture line; (3) the intravertebral sensory nerve endings are destroyed. Because of the exothermic and toxic effects of PMMA, which may damage the nerve endings in the bone, many initially believed that the last factor was the main reason for the pain relief after PMMA vertebroplasty, but later it was found that calcium phosphate vertebroplasty could achieve the same pain relief effect, so the damage to the nerve endings was not the only factor. The explanation of pain caused by distension of the posterior branch of the spinal nerve due to wedge compression of the vertebral body cannot be ruled out either. In China, Po et al. found a large distribution of posterior spinal nerve fibers in vertebrae, intervertebral discs and small joints of osteoporotic rats, which may be related to instability. In the case of vertebral tumors, after injecting bone cement, its mechanical effect can interrupt local blood flow, and its chemical toxic effect and polymerization heat can also cause necrosis of nerve endings in tumor tissues and their surrounding tissues to achieve pain relief, and even have the effect of killing tumor cells to some extent in a sense.